This invention relates to a television transmission system comprising a signal generator for producing a television signal which comprises a vision signal representing a sequence of pictures with each picture containing a plurality of sequential or interlaced lines and further comprises a motion information signal, each field of a picture being subdivided into a plurality of regions, a transmission channel for conveying said television signal from said generator to a television receiver in which the vision signal and motion information signal in the received television signal are processed to enable a television display to be provided. The invention also relates to a signal generator and a receiver for use with such a system.
Systems of the above type have been proposed for television transmissions where it is required, at the receiver, to up-convert the received signal to provide an enhanced vision signal having either a higher number of lines and/or a higher number of picture periods per second, the motion vectors being used to derive additional vision information for the additional lines and/or pictures from that received. In some proposals the motion information signal is conveyed in digital form and such proposals have been referred to as digitally assisted television (DATV).
One such system is described in "HDTV Bandwidth Reduction by Adaptive Subsampling and Motion-Compensation DATV Techniques" by G. A. Thomas, SMPTE Journal, Volume 96, No. 5, May 1987, pages 460-465, where each field of a picture is divided into a multiplicity of small blocks with a motion vector being generated for each block. Although the range of motion vectors may be severely restricted the transmission of the individual motion vectors for a field would occupy a considerable amount of space in the television signal though this may be reduced by sending a menu of the motion vectors and pointers as to the type of vector for each block.